2001 Suburban stalling issue

[Doubeleive]

Only notable ground issue's with the 800's is with the brake module and headlights that I can think of, I can't remember if it was the 800's or 900's having issue's with the fuel pump control module harness getting wet/corroded but it would be in the approx same location under the frame somewhere above the spare wheel. I was just thinking if you had a tech2 you could check everything when it shuts off and see if you can figure what gives the tech2 will tel you the commanded state of pretty much everything. there could be a dtc saved in there also that your off the shelf scanner won't read you need a tech2 or snap on, etc...

 

[kbuskill]

Only notable ground issue's with the 800's is with the brake module and headlights that I can think of, I can't remember if it was the 800's or 900's having issue's with the fuel pump control module harness getting wet/corroded but it would be in the approx same location under the frame somewhere above the spare wheel. I was just thinking if you had a tech2 you could check everything when it shuts off and see if you can figure what gives the tech2 will tel you the commanded state of pretty much everything. there could be a dtc saved in there also that your off the shelf scanner won't read you need a tech2 or snap on, etc...

Someone has pulled the big 60A fuse for the ABS. When we put a fuse in it the ABS module starts running constantly. My research tells me it is bad/cracked solder joints on the relay inside the module and reflowing the solder joints should fix it.

I did hook up my OBD2 adapter and use the Chevrosync app on my phone to look at the ABS codes and BCM codes and what not.

Like I said, it had like 50+ codes showing in the ECM which I believe was from it losing its ground causing it to freak out.

I will keep you guys posted. My buddy works a weird schedule so it may be a week or so before we get to check things out.

Thanks for all the input so far, keep it coming.

 

[Doubeleive]

and sometimes a broken ground on the injector harness which could probably be a cause of what is happening, that may be something to check

 

[kbuskill]

and sometimes a broken ground on the injector harness which could probably be a cause of what is happening, that may be something to check

Yeah, I was thinking injector harness or coil pack harness, that is why I wiggled and moved around all the harnesses to see if it would act up.

I was also thinking maybe the crank sensor or cam sensor. But with the fuel gauge not working when it acts up it leads me to believe it is some sort of grounding issue.

I also noticed the throttle body makes a high pitched noise when the key is in the run position with the engine off. I have read alot about guys having stalling issues with these trucks and cleaning the TB fixed their issue.

 

[sparkvark]

My 01 Yukon has a recall maybe 16 years ago for the fuel pump wire harness over heating. Maybe it wasn't done on this Suburban.

 

[kbuskill]

So my buddy dropped the fuel tank and replaced the fuel pump and pigtail harness.

The pump he pulled was a Delphi and the pump pigtail harness had already been replaced as evidenced by the heat shrink butt connectors that were on the harness.

I had him cut out the old butt connectors and harness and install the new ones on the chance that the old connectors weren't making good contact.

We also removed and cleaned the throttle body.

It ran good for 2-3 days and back to the same issue. Stalling or not starting with the fuel gauge reading zero.

When the fuel gauge reads properly it will start and run.

I am still leaning towards an intermittent ground issue or broken wire in the harness somewhere causing the random problem.

If the GMT800s are like the GMT900s then the gauges work off of the BCM which makes me suspect the BCM or it's wiring or the ECM or it's wiring.

I hate the idea of just throwing parts at it in hopes of fixing it..

I was really hoping that it would set a CEL so i could check the code and hopefully point us in the right direction but thus far that hasn't happened.

The ABS and BRAKE lights are still on. He removed the EBCM from the ABS unit and I opened it up and resoldered/reflowed the joints on the power leads, the relay, etc. But when we installed the 60A fuse for the ABS, the pump just continues to run constantly just as it did before so I guess the EBCM needs to be replaced. Although I am certain that is a separate issue from the stalling/no starting issue.

 

[exp500]

It sounds like a ground problem by the tank- It was better after wiggleing it for fuel pump swap.

 

[kbuskill]

It sounds like a ground problem by the tank- It was better after wiggleing it for fuel pump swap.

It was also better after cleaning the ground on the frame rail below the driver's door... it ran great for 2-3 days after that before acting up again.

I still believe it is a ground issue however. Next up will be getting him to clean the main grounds on the engine.

 

[Fless]

It was also better after cleaning the ground on the frame rail below the driver's door... it ran great for 2-3 days after that before acting up again.

I still believe it is a ground issue however. Next up will be getting him to clean the main grounds on the engine.

One of the grounds to check is the one in this video at 2:30. Supposedly it should connect to the engine block, but if the firewall to driver's side head ground is in good shape that should suffice.

 

[kbuskill]

One of the grounds to check is the one in this video at 2:30. Supposedly it should connect to the engine block, but if the firewall to driver's side head ground is in good shape that should suffice.

Thanks for the video, but that has already been remedied on his truck. I think I mentioned it earlier in this thread, but when he got the truck, the PO had spliced the two ground wires that go to the rear of the passenger head in the same manner as this video shows.

I don't like/trust butt connectors, especially the el cheapo ones like in this video, and the ones that the previous owner had used to make the repair so I had my buddy solder and heatshrink new wires onto them and ground them at the stud on the firewall.

I believe one of the two wires is the ground for the coil packs and the other is a ground for the oil pressure sensor but I'm not 100% sure.

I am skeptical that the braided ground strap is making good connection so that will probably be left in place but a new ground added to it between the firewall stud and the side of the alternator bracket, along with cleaning up the negative battery cable where it bolts to the engine.

Tech 2 should be delivered Tuesday so maybe we can get a better idea of what is actually going on next weekend. I will keep you all posted.